Currently own a 2006 BMW 325xi. I've had *most* of the routine maintenance kept up on the car. Now, today I've had some issues with the car idling rough and the acceleration stuttering a bit. I'm thinking it could be an ignition coil or a cylinder misfiring. On my drive home the check engine light did come on.

I actually just posted a thread with questions on this and it seems as though the coils go out fairly often (30k). I got the code P0302.. The last 2 digits tell you the cylinder so I bet your local auto store will read a similar code. Goodluck!

It actually wasn't related to the ignition coil. The problem exists w/ the VANOS solenoid.

Go to the DIY section and look for the thread on replacing the VANOS solenoids. It is a very easy DIY (if you turn wrenches on your car) and you can just clean and swap places of the two units (intake and exhaust). No need to get new parts. They just get dirty and need to be cleaned. 45 minute job at the most. I cleaned and swapped mine over 22,000 miles ago and have not had the problem reoccur.

So what the VANOS solenoid is is a short, thick, metal tune with holes in it and an inner rotary valve that moves to allow different combinations oil passages to open up. I guess they just get clogged up over time. Considering the solenoid part is an electronic component I just used CBC brand electronic parts cleaner and then shot some shop air at 90 PSI into all the orifices to clean everything up and dry them out.

Both exhaust and intake VANOS solenoids are the same part number. Swapping locations of the solenoids from intake to exhaust sides when re installing them lets them run different oil control profiles; because now one is controlling the exhaust cam rather than at its original location for controlling the intake cam and vice versa. In my thinking, swapping them keeps them from "running in" into just one set of the oil control routines and they get to act like new parts.

Thank you Eninty, I will be doing later today, the psi info was important, I was concerned about over doing it with the air, but at 90, that won't be an issue.

Look to the DIY for guidance. Make sure you don't drop the little mounting bolts into the cam chain cover, that would be really bad.

When you remove the solenoids, remove the mounting bolt completely from the mounting hole and put it on the work bench or tool box, just get it out of the engine bay before you pull the unit out of the head.

Take the top one out first and plug the hole with a shop rag. Then take the bottom one out and plug the hole with a rag. Clean both solenoids. Keep track of which one came from the top and bottom so you can switch them.

When replacing, pull the rag from the lower one first and replace the solenoid. Then pull the rag and replace the top unit. THEN bring both the mounting bolts back over to the engine and re-install the bolts.

I am helping a friend with this one- neither one of us have a garage, so we are attempting to tackle solenoids under a carport. I did exactly what ENINTY stated- used rags to cover the ports and did them in sequence starting with the upper one- minimizes chances of anything accidently dropping in the engine. I have cleaned and switched the solenoids but the vanos-related code and rough idle isn't going away. Perhaps, it is time to get a new set? Do the new ones come with new o-rings?

I am helping a friend with this one- neither one of us have a garage, so we are attempting to tackle solenoids under a carport. I did exactly what ENINTY stated- used rags to cover the ports and did them in sequence starting with the upper one- minimizes chances of anything accidently dropping in the engine. I have cleaned and switched the solenoids but the vanos-related code and rough idle isn't going away. Perhaps, it is time to get a new set? Do the new ones come with new o-rings?

So if one of the solenoids is bad, and you swapped them, the fault code should switch to the other cam. So if the fault code was on orginially on the exhaust side, it now should be on the intake side. Can't say about the o-rings. Just oder them when you get the parts to be sure.

So if one of the solenoids is bad, and you swapped them, the fault code should switch to the other cam. So if the fault code was on orginially on the exhaust side, it now should be on the intake side. Can't say about the o-rings. Just oder them when you get the parts to be sure.

Thank you Eninty and PeterM1. Yes, the fault switched and it appears that the exhaust-side solenoid has gone bad. I took the exhaust-side solenoid off my car and put into my friend's car (same car and model year), and the error code did not return after driving about 10 miles. So, I ordered a new one for my friend and we await delivery. They are actually not cheap, by our standards anyway.

Anyways, I have the exact same car - 06 325xi. Same issue. How did you guys pull the codes? My cousin has one of those computers (Not a BMW one) and it couldn't find anything. Did you guys take your car to the BMW dealership to get it repaired?

When I had my mechanic look at it, he replaced the Spark plugs and that didn't fix the issue.

this just to follow up my last post, my rough idling issue. so I did replace my ignition coil, just 1, everything works fine... until now I got another misfire, now its cylinder 6, I guess its on going, I am ordering another one.